Generally, in this type of door lock device, a lock device main unit B having the above three operating modes is mounted on an open/close free end side D1 of a door D in FIG. 1. In a prior art example, a knob for effecting the operation from the closed position holding condition to the locked condition and vice versa and a lever for effecting the operation from the closed position holding condition to the released condition are mounted on the interior side of the door, the knob and lever being connected with the lock device main unit by individual rods for transmitting the knob movement and lever movement, respectively, to the lock device main unit B.
Such a door lock device has had the various problems described below because the rods are non-elastic rigid members. There are at least four problems.
A stick or the like is inserted between the door body and the door window from outside the vehicle so that the rods are operated to put the lock device into the released condition and thus open the door, and articles inside the vehicle are stolen.
When the vehicle collides, there is a possibility that the rods may be mechanically bent and the lock device main unit may be put into the same condition as if the rods are pulled, that is, into the released condition, causing the door to open and thus exposing passengers to danger.
If the prescribed route along which the rods are to be installed in the vehicle door is bent, it is difficult to install the rods along the prescribed route when assembling the lock device onto the door, and the assembling work efficiency is impaired.
Assembling the lock device to the door demands close dimensional tolerances on the positional relationship between the lock device main unit and the knob and lever, and the assembling work has to be done with care, which requires a lot of time and work.
To solve the above-enumerated problems, there is proposed the following construction. That is, an operating member for effecting the operation to switch between the closed position holding condition, lock condition, and released condition is provided in the lock device main unit, the operating member being made switchable between three positions, i.e., an unlocked position, a locked position, and a released position. In the main unit, an engaging member for engaging a latch member that engages on a striker is interlocked with the operation of the operating member such that when the operating member is in the released position, engagement of the latch member by the engaging member is released, and when the operating member is in any of the other positions, the latch is engaged with the engaging member. Further, a locking lever for switching the door lock device between the unlocked and locked conditions is interlocked with the operation of the operating member such that when the operating member is in the locked position, the locking lever is in the locked condition, and when the operating member is in any of the other positions, the locking lever is in the unlocked condition. On the other hand, an operating handle for switching the mode between the closed position holding condition, locked condition, and released condition is mounted on the interior side of the door. This operating handle is connected with the operating member in the lock device main unit by a flexible cable. Such a construction is proposed (for example, in European Patent Application No. 169644).
In the above construction, since the cable for connecting the lock device main unit with the operating handle in interlocking relationship is flexible, the cable cannot be operated with a stick or the like from outside the vehicle, thus providing excellent security against theft. Furthermore, since the cable, if bent in the event of a vehicle collision, does not cause the operating member in the lock device main unit to switch from one position to another, there is no danger of accidental switching into the released condition, and safety can thus be secured for vehicle passengers. Moreover, when assembling the lock device to the door, since the cable can be installed by being bent freely, the assembly work is easy, and since the assembling does not demand strict positional relationship between the lock device main unit and the operating member, the assembling work can be done without special care. Further, although the cable which has the various advantages described above is expensive, the above construction requires only one such cable and the cost increase associated with the use of the cable, therefore, is reduced, which, coupled with the fact that only one cable is necessary and with the resulting reduction in the number of steps in cable assembling work, offers the effect of being able to implement the construction at a relatively low cost.
In the above-constructed door lock device, the interlocking operation between the operating member and locking lever in the lock device main unit is accomplished by the construction shown in FIG. 27. That is, the locking lever 161 pivotably mounted on a housing 160 has two flanges 162 and 163. The operating member 166, which is constructed to be movable forward and backward by an inner wire 165 of the interlinking cable 164, has a disc 167 at one portion thereof, and the disc 167 is located between the two flanges 162 and 163. Between the flange 162 and the disc 167 is interposed a coil spring 168 which urges the disc 167 toward the flange 163 with respect to the locking lever 161. The member indicated at 169 in the operating member 166 is an interlocking portion for interlocking with the engaging member.
In the above construction, with the locking lever 161 staying in the unlocked condition (the closed position holding condition) shown by the solid line, when the wire 165 is pushed downward in the figure to switch to the locked mode (the locked condition), the flange 163 is pushed by the disc 167, which causes the locking lever 161 to move to the position indicated by the two-dot chain line and thus into the locked condition. In the locked condition, when the wire 165 is pulled in the opposite direction, the flange 162 is pushed by the disc 167 via the spring 168, thus returning the locking lever to the unlocked condition.
In the unlocked condition, when the wire 165 is further pulled to effect switching to the released condition, the locking lever 161 is not displaced but the spring 168 is only compressed by the disc 167, and the engagement with the engaging member is released by the movement of the interlocking portion 169.
The above construction has had the problem that a force equal to the sum of the force needed to release the engagement with the engaging member and the force needed to compress the spring 168 has to be applied at the operating handle in order to effect the switching to the released condition, thus increasing the operating force of the operating handle.
On the other hand, if the force of the spring 168 is reduced to lessen the operating force, there arises the problem that when the movement of the locking lever 161 becomes heavy because of freezing or rusting due to aging, even if the operating handle is operated to effect unlocking from the locked condition the locking lever 161 remains fixed in the position indicated by the two-dot chain line while the spring 168 is being compressed, making it impossible to effect release from the locked condition.
Using only one handle to control the three operations, i.e., the operations between the locked position, unlocked position, and released position, is very convenient. But, sometimes, there are cases where while the vehicle is slowing down and is coming to a stop, the passenger pulls the handle successively until accidentally putting it into the released position when he just intends to operate the handle from the locked position to the unlocked position. If this happens, there is a danger that the vehicle door may be opened while the vehicle is slowing down.
The door lock device of the present invention is provided to solve the above-described problems associated with the prior art, and an object of the invention is to provide a door lock device capable of effecting the operation to switch between the three modes, i.e., the closed position holding condition, the locked condition, and the released condition.
Another object of the invention is to permit the connection between the operating handle and the lock device main unit by a cable, ensures the prevention of theft and the safety in the event of a collision, and facilitate assembling to the door.
A further object of the invention is to enable the construction using only one cable to be implemented at a relatively low cost.
A further object of the invention is to enable the operation from the unlocked condition to the released condition to be effected with a relatively light operating force, without using a spring as in the prior art, in the construction using one cable to accomplish the operation of the three modes.
A further object of the invention is to ensure reliable switching from the locked condition to the unlocked condition by the operation of the operating handle, without using a spring as in the prior art, even when the member for effecting the switching between the unlocked condition and the locked condition becomes difficult to move because of freezing or rusting due to aging.
Still another object of the invention is to enable the operation from the unlocked position to the released position to be made different from the operation from the locked position to the unlocked position, if necessary, in a construction that allows the three mode operations between the locked position, unlocked position, and released position to be carried out using only one handle.
Other objects and advantages of the present invention will become more apparent from the accompanying drawings and the following description given in conjunction with the drawings.